awk for loop error when using if else -

here datafile t2, separated tab

_ibaseebna1_1 0.79(0.28-2.22) 0.6540 _ibaseebna1_2 0.88(0.48-1.62) 0.6900 _ibaseebna1_3 0.78(0.32-1.86) 0.5700 ptrend 0.93(0.72-1.20) 0.5800 _ibaseebna1_1 1.85(0.60-5.73) 0.2850 _ibaseebna1_2 1.89(0.57-6.27) 0.2950 _ibaseebna1_3 3.21(1.00-10.33) 0.0510 ptrend 1.39(1.05-1.85) 0.0200 pinteraction 1.39(0.93-2.10) 0.1120 

i want remove value of second column if $1==ptrend or ==pinteraction.

the results should like:

_ibaseebna1_1 0.79(0.28-2.22) 0.6540 _ibaseebna1_2 0.88(0.48-1.62) 0.6900 _ibaseebna1_3 0.78(0.32-1.86) 0.5700 ptrend     0.5800 _ibaseebna1_1 1.85(0.60-5.73) 0.2850 _ibaseebna1_2 1.89(0.57-6.27) 0.2950 _ibaseebna1_3 3.21(1.00-10.33) 0.0510 ptrend     0.0200 pinteraction     0.1120  

i can use code :

awk -f' ' ' {                if ( $1=="ptrend" ) print $1," "," ",$3;                else                if ( $1=="pinteraction" ) print $1," "," ",$3;                else                print $0; }' t2.txt > t3.txt 

but when try use loop:

for in ptrend pinteraction  awk -f' ' -v p=$i '{                 if ( $1==p ) print $1," "," ",$3;                 else                 print $0; }' t2.txt > t3.txt done 

which give results :

_ibaseebna1_1 0.79(0.28-2.22) 0.6540 _ibaseebna1_2 0.88(0.48-1.62) 0.6900 _ibaseebna1_3 0.78(0.32-1.86) 0.5700 ptrend 0.93(0.72-1.20) 0.5800 _ibaseebna1_1 1.85(0.60-5.73) 0.2850 _ibaseebna1_2 1.89(0.57-6.27) 0.2950 _ibaseebna1_3 3.21(1.00-10.33) 0.0510 ptrend 1.39(1.05-1.85) 0.0200 pinteraction     0.1120 

anything wrong loop?

the fundamental problem loop is loop. writing shell loop manipulate text wrong approach. can describe in 1 brief, trivial awk command no surrounding shell loop:

awk '!/^_/{$2=""}1' t2